1. Field of the Invention
The present invention relates to a device and a method for operating an internal combustion engine having a plurality of pistons displaceable inside cylinders, in which: fuel is injected directly into the cylinders; a standstill position of at least one piston inside a cylinder in which the internal combustion engine is at a standstill is determined; and a starting cylinder into which fuel is injected first is selected for a start following the standstill.
2. Description of Related Art
Such a method may be used in what is known as a starter-supported direct start of an internal combustion engine of a motor vehicle. In the starter-supported direct startup, the internal combustion engine is to start as quickly as possibly with minimum support of the starter and with the lowest possible noise development. This requires a startup operation to be implemented in such a way that a starter is driving the internal combustion engine for the shortest time possible. To achieve short startup periods, the starting cylinder, i.e., the particular cylinder into which fuel is injected first and which is fired first in the startup of the internal combustion engine is selected in a suitable manner for each startup operation. A compromise between two contradictory effects must be sought in the selection of the starting cylinder. For one, to avoid delays in the startup operation, a starting cylinder should be selected whose piston is as close as possible to a position that is suitable for the injection of fuel into a cylinder and for firing the fuel. For another, however, to obtain an acceptably low probability of a false start, no cylinder should be selected whose piston is too close to a position that is suitable for the injection and the firing. For a false start would go hand-in-hand with a termination and a subsequent new beginning of the startup operation, which would lead to considerable delays in the startup of the internal combustion engine.
From published German patent document DE 10 2004 037 129, a device and a method are known for the control of an internal combustion engine in a startup. In this method, a starting cylinder is determined as a function of the position of the individual pistons within their cylinders. When determining the starting cylinder, the individual cylinders of the internal combustion engine are checked in a sequence that corresponds to a firing sequence, until a suitable cylinder is found.